It is well known to provide a clamp for a lift truck having clamp arms which are connected to slides moving within parallel guides and actuated by a hydraulic piston and cylinder assembly. The various problems of stress concentration and failures in the slides and their connections to the clamp arms is discussed in U.S. Pat. No. 4,185,944.
It is important to have a clamp arm and slide mechanism which has the necessary strength, at a low cost, with low weight, but one that can be inexpensively and easily repaired or replaced. However, the achievement of one of these objectives is generally at the expense of other of the objectives. For example, the strength can be increased by providing a solid slide with the clamp arms welded thereto. However, this solution increases the weight undesirably, increases the cost, and increases the cost and difficulty of repairs. On the other hand, using a tubular slide advantageously decreases the weight and cost, but disadvantageously reduces the strength, and bolted connections generally further weaken a member.
The present invention is directed to an improved slide and clamp arm connection which reduces weight, cost, allows easy replacement at low cost, while increasing the strength of a tubular member with holes.